As advised, I posed this to the MARKUP list yesterday, and so we'll see if there is any community input. That query includes a bit more information about the role of the enotikon: "The enotikon serves is a lexical aid in scriptio continua, serving not to divide words from one another (for which purpose there is the diastole or hypodiastole) but instead to indicate that a single word is meant. A good example of a text that requires it is PSI 16 1594.6, where it indicates πρ]ο̣σγενό̣μ[ένοι] (instead...
Add scribal indication of metrical quantity & scribal enotikon (=hyphen)